Referring to FIG. 1, a conventional bicycle wheel 1 includes a central hub 11, a rim 12 and a spoke unit 13 that is connected between the central hub 11 and the rim 12. The spoke unit 13 includes a plurality of first spokes 131 and a plurality of second spokes 132, each of which extends between the rim 12 and the central hub 11. The central hub 11 includes a hub body 110 that has first and second ends opposite to each other, a first hub flange 111 that radially extends from the first end of the hub body 110 and is connected to the first spokes 131, a second hub flange 112 that radially extends from the second end of the hub body 110 and is connected to the second spokes 132, and a driven portion 113 disposed at the second end of the hub body 110 and adjacent to the second hub flange 112.
While the driven portion 113 is driven by a rider to rotate the bicycle wheel 1, the tension applied to the rim 12 and the spoke unit 13 is unbalanced since the driving portion 113 is closer to the second hub flange 112 as compared to the first hub flange 111. Strength and durability of the rim 12 and the spoke unit 13 are reduced due to the unbalanced tension.